A SOCS-1 promoter variant is associated with total serum IgE levels

Aberrant expression of suppressor of cytokine signaling (SOCS) molecules contributes to the development of allergic diseases

Suppressor of cytokine signalling (SOCS) proteins bind to certain cytokine receptors, Janus kinases and signalling molecules to regulate signalling pathways, thus controlling immune and inflammatory responses. Dysregulated expression of various types of SOCS molecules was indicated in multiple types of allergic diseases. SOCS1, SOCS2, SOCS3, SOCS5, and cytokine-inducible SH2 domain protein (CISH) can differentially exert anti-allergic impacts through different mechanisms, such as suppressing Th2 cell development and activation, reducing eosinophilia, decreasing IgE production, repressing production of pro-allergic chemokines, promoting Treg cell differentiation and activation, suppressing Th17 cell differentiation and activation, increasing anti-allergic Th1 responses, inhibiting M2 macrophage polarization, modulating survival and development of mast cells, reducing pro-allergic activity of keratinocytes, and suppressing pulmonary fibrosis. Although some anti-allergic effects were attributed to SOCS3, it can perform pro-allergic impacts through several pathways, such as promoting Th2 cell development and activation, supporting eosinophilia, boosting pro-allergic activity of eosinophils, increasing IgE production, enhancing the expression of the pro-allergic chemokine receptor, reducing Treg cell differentiation, increasing pro-allergic Th9 responses, as well as supporting mucus secretion and collagen deposition. In this review, we discuss the contrasting roles of SOCS proteins in contexts of allergic disorders to provide new insights regarding the pathophysiology of these diseases and possibly explore SOCS proteins as potential therapeutic targets for alleviating allergies.

The genetic effect and molecular function of the SOCS5 in the prognosis of esophageal squamous cell carcinoma

Expression of cytokines and growth factors have been shown to be highly correlated with the prognosis of esophageal squamous cell carcinoma (ESCC), a deadly disease with poor prognosis. The suppressor of cytokine signaling (SOCS) family of proteins are key factors in regulating cytokines and growth factors. Yet the role of the SOCS proteins in ESCC is hardly investigated. We currently investigated the prognostic role of SOCS5 in ESCC. We analyzed the prognostic effects of 16 single nucleotide polymorphisms (SNPs) within the SOCS genes in 632 ESCC patients. We repeatedly observed that the 3 SNPs in SOCS5, SOCS5:rs3814039, SOCS5:rs3738890, and SOCS5: rs3768720, were significantly correlated with both overall (OS) and progression-free survival (PFS) of ESCC patients (rs3814039, p=0.032 for OS and p=0.009 for PFS; rs3738890, p=0.016 for OS, and p=0.008 for PFS; rs3768720, p=0.005 for OS and p=0.002 for PFS). SOCS5: rs3768720 was also significantly associated with distant metastasis (Ptrend=0.028). The luciferase assay revealed that SOCS5:rs3814039 and SOCS5: rs3768720 might influence the prognosis by regulating SOCS5 expression. Functional analysis demonstrated SOCS5 was able to regulate epidermal growth factor receptor (EGFR) expression and migration activity of ESCC cells. Furthermore, Patients with strong SOCS5 in normal tissues exhibited significantly better PFS (P=0.049) and reduced risk of distant metastasis (P=0.004) compared to those with weak SOCS5 expression. Overall, our study demonstrates the novel function of SOCS5 in ESCC prognosis. The genetic polymorphisms and expression of SOCS5 could serve as a novel therapeutic biomarker for improving the prognosis of ESCC.

Negative Regulation of Cytokine Signaling in Immunity

Cytokines are key modulators of immunity. Most cytokines use the Janus kinase and signal transducers and activators of transcription (JAK-STAT) pathway to promote gene transcriptional regulation, but their signals must be attenuated by multiple mechanisms. These include the suppressors of cytokine signaling (SOCS) family of proteins, which represent a main negative regulation mechanism for the JAK-STAT pathway. Cytokine-inducible Src homology 2 (SH2)-containing protein (CIS), SOCS1, and SOCS3 proteins regulate cytokine signals that control the polarization of CD4+ T cells and the maturation of CD8+ T cells. SOCS proteins also regulate innate immune cells and are involved in tumorigenesis. This review summarizes recent progress on CIS, SOCS1, and SOCS3 in T cells and tumor immunity.

New perspectives on the regulation of type II inflammation in asthma

Asthma is a chronic inflammatory disease of the lungs which has been thought to arise as a result of inappropriately directed T helper type-2 (Th2) immune responses of the lungs to otherwise innocuous inhaled antigens. Current asthma therapeutics are directed towards the amelioration of downstream consequences of type-2 immune responses (i.e. β-agonists) or broad-spectrum immunosuppression (i.e. corticosteroids). However, few approaches to date have been focused on the primary prevention of immune deviation. Advances in molecular phenotyping reveal heterogeneity within the asthmatic population with multiple endotypes whose varying expression depends on the interplay between numerous environmental factors and the inheritance of a broad range of susceptibility genes. The most common endotype is one described as "type-2-high" (i.e. high levels of interleukin [IL]-13, eosinophilia, and periostin). The identification of multiple endotypes has provided a potential explanation for the observations that therapies directed at typical Th2 cytokines (IL-4, IL-5, and IL-13) and their receptors have often fallen short when they were tested in a diverse group of asthmatic patients without first stratifying based on disease endotype or severity. However, despite the incorporation of endotype-dependent stratification schemes into clinical trial designs, variation in drug responses are still apparent, suggesting that additional genetic/environmental factors may be contributing to the diversity in drug efficacy. Herein, we will review recent advances in our understanding of the complex pathways involved in the initiation and regulation of type-2-mediated immune responses and their modulation by host factors (genetics, metabolic status, and the microbiome). Particular consideration will be given to how this knowledge could pave the way for further refinement of disease endotypes and/or the development of novel therapeutic strategies for the treatment of asthma .

Global gene regulation during activation of immunoglobulin class switching in human B cells

Immunoglobulin class switch recombination (CSR) to IgE is a tightly regulated process central to atopic disease. To profile the B-cell transcriptional responses underlying the activation of the germinal centre activities leading to the generation of IgE, naïve human B-cells were stimulated with IL-4 and anti-CD40. Gene expression and alternative splicing were profiled over 12 days using the Affymetrix Human Exon 1.0 ST Array. A total of 1,399 genes, forming 13 temporal profiles were differentially expressed. CCL22 and CCL17 were dramatically induced but followed a temporal trajectory distinct from classical mediators of isotype switching. AICDA, NFIL3, IRF4, XBP1 and BATF3 shared a profile with several genes involved in innate immunity, but with no recognised role in CSR. A transcription factor BHLHE40 was identified at the core of this profile. B-cell activation was also accompanied by variation in exon retention affecting >200 genes including CCL17. The data indicate a circadian component and central roles for the Th2 chemokines CCL22 and CCL17 in the activation of CSR.

Suppressor of Cytokine Signaling (SOCS)1 Regulates Interleukin-4 (IL-4)-activated Insulin Receptor Substrate (IRS)-2 Tyrosine Phosphorylation in Monocytes and Macrophages via the Proteasome

Allergic asthma is a chronic lung disease initiated and driven by Th2 cytokines IL-4/-13. In macrophages, IL-4/-13 bind IL-4 receptors, which signal through insulin receptor substrate (IRS)-2, inducing M2 macrophage differentiation. M2 macrophages correlate with disease severity and poor lung function, although the mechanisms that regulate M2 polarization are not understood. Following IL-4 exposure, suppressor of cytokine signaling (SOCS)1 is highly induced in human monocytes. We found that siRNA knockdown of SOCS1 prolonged IRS-2 tyrosine phosphorylation and enhanced M2 differentiation, although siRNA knockdown of SOCS3 did not affect either. By co-immunoprecipitation, we found that SOCS1 complexes with IRS-2 at baseline, and this association increased after IL-4 stimulation. Because SOCS1 is an E3 ubiquitin ligase, we examined the effect of proteasome inhibitors on IL-4-induced IRS-2 phosphorylation. Proteasomal inhibition prolonged IRS-2 tyrosine phosphorylation, increased ubiquitination of IRS-2, and enhanced M2 gene expression. siRNA knockdown of SOCS1 inhibited ubiquitin accumulation on IRS-2, although siRNA knockdown of SOCS3 had no effect on ubiquitination of IRS-2. Monocytes from healthy and allergic individuals revealed that SOCS1 is induced by IL-4 in healthy monocytes but not allergic cells, whereas SOCS3 is highly induced in allergic monocytes. Healthy monocytes displayed greater ubiquitination of IRS-2 and lower M2 polarization than allergic monocytes in response to IL-4 stimulation. Here, we identify SOCS1 as a key negative regulator of IL-4-induced IRS-2 signaling and M2 differentiation. Our findings provide novel insight into how dysregulated expression of SOCS increases IL-4 responses in allergic monocytes, and this may represent a new therapeutic avenue for managing allergic disease.

A Novel Association of the Suppressor of Cytokine Signaling 1 (SOCS1) Gene Polymorphisms in Ischemic Stroke Patients

Ischemic stroke is a common neurological disease and a leading cause of permanent disability in many countries. Recent studies provide evidence on the role of the suppressor of the cytokine signaling 1 (SOCS1) gene in the development and progression of atherosclerotic lesions. However, few studies have assessed the association between single nucleotide polymorphisms (SNPs) on SOCS1 gene and ischemic stroke. Therefore, the present study aimed to investigate the role of SOCS1 polymorphism in ischemic stroke risk in a northern Chinese Han population. We examined 475 patients with ischemic stroke and 486 normal controls. Three SNPs (rs243327, rs243330, and rs33932899) of SOCS1 gene were determined for TaqMan genotyping assays. We also classified these case samples in depth by complications with hypertension or diabetes and by ischemic stroke subtypes. When adjusting models by multiple factor analysis by logistic regression, then calculated 10,000 permutations were performed for each model to correct the multiple test. Under additive model, the rs243327 was associated with ischemic stroke with hypertension (p = 0.047). Under heterozygous model, the rs33932899 and rs243330 were significantly associated with ischemic stroke subtypes by atherosclerosis (p = 0.038, p = 0.048, respectively). In summary, our data demonstrated for the first time that the polymorphisms of the SOCS1 gene are associated with the risk of ischemic stroke in a northern Chinese Han population, suggesting that SOCS1 gene polymorphisms may play an important role in the pathogenesis of ischemic stroke.

Regulation of Macrophage, Dendritic Cell, and Microglial Phenotype and Function by the SOCS Proteins

Macrophages are innate immune cells of dynamic phenotype that rapidly respond to external stimuli in the microenvironment by altering their phenotype to respond to and to direct the immune response. The ability to dynamically change phenotype must be carefully regulated to prevent uncontrolled inflammatory responses and subsequently to promote resolution of inflammation. The suppressor of cytokine signaling (SOCS) proteins play a key role in regulating macrophage phenotype. In this review, we summarize research to date from mouse and human studies on the role of the SOCS proteins in determining the phenotype and function of macrophages. We will also touch on the influence of the SOCS on dendritic cell (DC) and microglial phenotype and function. The molecular mechanisms of SOCS function in macrophages and DCs are discussed, along with how dysregulation of SOCS expression or function can lead to alterations in macrophage/DC/microglial phenotype and function and to disease. Regulation of SOCS expression by microRNA is discussed. Novel therapies and unanswered questions with regard to SOCS regulation of monocyte-macrophage phenotype and function are highlighted.

Association of SOCS1 (- 820) (rs33977706) gene polymorphism with chronic periodontitis: A case-control study in Brazilians

It is evident that the accumulation of periodontal pathogens over the teeth surface triggers periodontitis; however, its aggravation and severity depend on other elements such as environmental factors, systemic health and the host genetic and/or epigenetic background. To address this issue, we investigated the association of two genetic polymorphisms placed on promoter region of SOCS1 gene with chronic periodontal disease. SOCS1 regulates Jak/Kinase signaling pathway and changes in its mRNA expression have been related to different types of cancer and chronic inflammation, including chronic periodontitis. The frequency of alleles and genotypes of two polymorphisms in SOCS1 gene promoter (position − 820 (rs33977706) and position − 1478 (rs33989964)) were analyzed by performing RFLP and TaqMan system in a total of 257 non-smoking subjects. We found a low frequency of A allele and A/A genotype of SOCS1^− 820 polymorphism in the chronic periodontitis group, especially when severe periodontitis samples were separately analyzed (OR = 0.3933; p = 0.0084 (IC95% 0.2112 < μ < 0.7324)), suggesting that A allele plays protective effect against chronic periodontitis. We did not find association between SOCS1-1478 polymorphism and periodontitis. In addition, analysis of SOCS1^{− 820/− 1478} haplotype revealed that the frequency of A^− 820/CA^− 1478 haplotype decreases in ChrP (p = 0.0089). In conclusion, our study found that SOCS1^− 820 polymorphism is associated with chronic periodontitis.

Association of the suppressor of cytokine signaling 1 (SOCS1) gene polymorphisms with acute coronary syndrome in Mexican patients

Recent studies provide evidence on the emerging role of the SOCS1 gene in the development and progression of atherosclerotic lesions. This gene encodes for the suppressor of the cytokine signaling-1 protein that interacts directly with the Janus kinases that are essential intracellular mediators of the immune cytokine action. The aim of this study was to test for associations between SOCS1 gene single nucleotide polymorphisms (SNPs) and the risk of developing acute coronary syndromes (ACS) in a group of Mexicans patients. Four SNPs [-3969 C>T (rs243327), -1656 G>A (rs243330), -820 G>T (rs33977706) and +1125 G>C (rs33932899)] of SOCS1 gene were determined for TaqMan genotyping assays in a group of 447 patients with ACS and 622 healthy controls. Under heterozygous model, the -3969 C>T (rs243327) SNP was associated with increased risk of ACS (OR=1.45, P(Het)=0.021). On the other hand, under co-dominant and heterozygous models, the -1656 G/A (rs243330) SNP was associated with increased risk of ACS (OR=1.47, P(Co-dom)=0.038 and OR=1.50, P(Het)=0.013, respectively). Moreover, under co-dominant, dominant, and heterozygous models, the -820T/G (rs33977706) SNP was associated with increased risk of ACS (OR=1.59, P(Co-dom)=0.03, OR=1.48, P(Dom)=0.028 and OR=1.61, P(Het)=0.01). Finally, under co-dominant and heterozygous models, the +1125 G/C (rs33932899) SNP was associated with increased risk of ACS (OR=1.54, P(Co-dom)=0.006, OR=1.58, P(Het)=0.012, respectively). Models were adjusted for gender, age, body index mass, dyslipidemia, alcohol consumption, and smoking. In summary, our data suggests that the four studied polymorphisms of the SOCS1 gene play an important role as susceptibility markers for developing ACS.

Negative regulation of human mononuclear phagocyte function

At mucosal surfaces, phagocytes such as macrophages coexist with microbial communities; highly controlled regulation of these interactions is essential for immune homeostasis. Pattern-recognition receptors (PRRs) are critical in recognizing and responding to microbial products, and they are subject to negative regulation through various mechanisms, including downregulation of PRR-activating components or induction of inhibitors. Insights into these regulatory mechanisms have been gained through human genetic disease-association studies, in vivo mouse studies utilizing disease models or targeted gene perturbations, and in vitro and ex vivo human cellular studies examining phagocytic cell functions. Although mouse models provide an important approach to study macrophage regulation, human and mouse macrophages exhibit differences, which must be considered when extrapolating mouse findings to human physiology. This review discusses inhibitory regulation of PRR-induced macrophage functions and the consequences of dysregulation of these functions and highlights mechanisms that have a role in intestinal macrophages and in human macrophage studies.

SOCS, Inflammation, and Autoimmunity

Cytokines play essential roles in innate and adaptive immunity. However, excess cytokines or dysregulation of cytokine signaling will cause a variety of diseases, including allergies, autoimmune diseases, inflammation, and cancer. Most cytokines utilize the so-called Janus kinase–signal transducers and activators of transcription pathway. This pathway is negatively regulated by various mechanisms including suppressors of cytokine signaling (SOCS) proteins. SOCS proteins bind to JAK or cytokine receptors, thereby suppressing further signaling events. Especially, suppressor of cytokine signaling-1 (SOCS1) and SOCS3 are strong inhibitors of JAKs, because these two contain kinase inhibitory region at the N-terminus. Studies using conditional knockout mice have shown that SOCS proteins are key physiological as well as pathological regulators of immune homeostasis. Recent studies have also demonstrated that SOCS1 and SOCS3 are important regulators of helper T cell differentiation and functions. This review focuses on the roles of SOCS1 and SOCS3 in T cell mediated inflammatory diseases.

ERK1 is important for Th2 differentiation and development of experimental asthma

The ERK1/2 signaling pathway regulates a variety of T-cell functions. We observed dynamic changes in the expression of ERK1/2 during T-helper cell differentiation. Specifically, the expression of ERK1/2 was decreased and increased by IL-12 and IL-4, respectively. To address this subject further, we examined the specific role of ERK1 in Th2 differentiation and development of experimental asthma using ERK1(-/-) mice. ERK1(-/-) mice were unable to mount airway inflammation and hyperreactivity in two different models of asthma, acute and chronic. ERK1(-/-) mice had reduced expression of Th2 cytokines IL-4 and IL-5 but not IL-17A or IFN-γ. They had reduced levels of allergen-specific IgE and blood eosinophils. T cells from immunized ERK1(-/-) mice manifested reduced proliferation in response to the sensitizing allergen. ERK1(-/-) T cells had reduced and short-lived expression of JunB following TCR stimulation, which likely contributed to their impaired Th2 differentiation. Immunized ERK1(-/-) mice showed reduced numbers of CD44(high) CD4 T cells in the spleen. In vitro studies demonstrated that Th2 but not Th1 cells from ERK1(-/-) mice had reduced numbers of CD44(high) cells. Finally, CD4 T cells form ERK1(-/-) mice expressed higher levels of BIM under growth factor-deprived conditions and reduced Mcl-1 on stimulation. As a result, the survival of CD4 T cells, especially CD44(high) Th2 cells, was much reduced in ERK1(-/-) mice. We conclude that ERK1 plays a nonredundant role in Th2 differentiation and development of experimental asthma. ERK1 controls Th2 differentiation and survival through its effect on JunB and BIM, respectively.